非连续变形分析的MLS后处理方法

MLS-Based Postprocessing Procedure for Discontinuous Deformation Analysis

非连续变形分析(discontinuous deformatrion analysis,DDA)通过引入虚拟节理网格将块体离散成子块体系统进行断裂扩展数值模拟.针对这种方法难以获得精确块体应力分布的问题,提出一种基于无网格法移动最小二乘(moving least squares,MLS)插值的应力恢复算法.利用DDA计算得到的节点位移,通过恰当构造MLS形函数及其导数,推导了块体任意点应力的计算公式.数值算例将基于MLS后处理的结果与解析解及平均值法后处理结果进行比较,验证了所提出方法的精确性和有效性.

The discontinuous deformation analysis （DDA） simulates fracture propagations by introducing fictitious joint meshes in blocks to generate sub-blocks. In order to obtain accurate stress distributions with this method, a stress recovery procedure was proposed based on the moving least squares （MLS） interpolation technique. With the MLS shape functions and their derivatives, the stress at any point within a block can be expressed by means of nodal displace- ments. Numerical examples were given to verify the accuracy and effectiveness of the proposed method. Comparison of the stress results between the analytical method, the averaging postpro- cessing method and the proposed MLS-based postprocessing procedure indicates that, the MLS- based stress recovery procedure is of high accuracy in providing more reliable block stress dis- tributions,